Effectiveness of acid-treated agricultural stones used in biopurification systems to avoid pesticide contamination of water resources caused by direct losses: mathematical modelling and thermodynamical study

Abstract

Despite the availability of various clean-up methods, the bio-adsorption remains one of the most effective processes used for pesticides removal. In order to evaluate the possible application of low cost organic waste materials at small scale, a series of experiments were performed using natural and activated olive, date and avocado stones. The mathematical modeling of endosulfan metabolites adsorption has been carried out under equilibrium conditions. Experimental adsorption data were modeled by Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherms. The mean adsorption free energy derived from the D–R isotherm model showed that the pesticides adsorption was taken place by weak physical forces. The calculated thermodynamic parameters prove that pesticides adsorption on acid-treated stones was feasible, spontaneous and exothermic under examined conditions.